Abstract— Safety of man, machines and freightis of significant concern in modern automobiles. Sensors used for advanceddriver assistance systems, assist the driver during dangerous situations,thereby ensuring high safety standards.
Proximity Sensor used in ParkingAssistance Systems, are some of the key feature in the Sensors Used for AdvancedDriver Assistance Systems. Parking Assistance system uses various sensors likeUltrasonic Systems and Electromagnetic Systems inputs data and Microcontrollersin calculating positions and navigating vehicles. This paper will give overviewsof various sensors used for Advanced Driver Assistance Systems with theirrespective references and describes the state of the art for Sensors Used forAdvanced Driver Assistance Systems and future technological development, withfocus on Ultrasonic Systems of the Proximity Sensor and will give an overviewof proximity sensors and applications of the ultrasonic system. The demand for Sensors used for AdvancedDriver Assistance Systems are needed has a result of the need to manufacturesafer vehicles in order to reduce the number of road accidents.
Today, AdvancedDriver Assistance Systems uses input data from sensors like proximity sensors,radar sensors, laser sensors, blind spot monitor sensors, gps sensors andpressure sensors, etc to work in real time by giving warnings to drivers or bytaking charge of the control systems immediately. This technologies arecontrolled by complex real time embedded systems. There are different sensors used for advanced driverassistance systems, each of these sensors provide different functions to theuser. Most of these sensors are paramount to the safety of the driver whileothers makes it possible for the driver to be able to avoid minor accidentswithout difficulty (see Table 1).Sensors used for advanceddriver assistance systems, should be able to reliably and accurately detect theenvironment as a type of “attentive passenger”. Proximity sensors are mostlyused in Parking Assistance Systems. The sensors are designed for vehicles, toalert drivers of close obstacles in their part while parking without anyphysical contact with the obstacles 1. Proximity sensors makes use of (seeFigure 1) either Ultrasonic System or an Electromagnetic Systems: which worksby searching for differences in electromagnetic fields that are emitted duringthe process and then, returns a signal.
An example of this type of system, isthe “Electromagnetic induction (EMI) sensor”. A scientific paper written byL.D. Landau and E.M. Lifshitz, illustrates the working principle of theelectromagnetic induction (EMI) sensor 2.
Ultrasonicproximity sensors are mainly used in vehicles, to calculate and determine achange in position, level measurement and detect the distance to nearbyobjects. Ultrasonic proximity sensors, emits acoustic pulses and has a controlunit which calculates the propagation time of (see Figure 2) each reflectingsignal 3. This process ensures that the sensors are able to detect objectindependent of its color rendering, the design and surface type 4. It ispossible to correctly detect even materials such as transparent objects, glass,etc. One of the disadvantages of ultrasonic sensors is that; they do not have avery good sensitivity towards dirt and can be easily affected by environmentalfactors 5. Resistance thermometers and thermocouples are the two conventionalmethods of measuring temperature. This methods are used as a result of wave proagationchanges that notably occur openly to all parameters with temperature.A.
Pressure Measurement Other principles are used when measuring pressure in a process this isas a result that, ultrasound can not directly measure pressure. B. Level and Distance MeasurementUltrasonic sensors emits acoustic pulses, radiation or beampatterns, which are relative to the sensitivity of a transducer as a functionof spatial angle 6. Ultrasonic sensors always generate a different beampattern from that of its transducer. A technique used for realizing level anddistance measurement is the ultrasound reflection technique. Two differenttypes of distance and level instruments are used: binary and continuousinstruments.
A scientific paper written by M.B. Gitisand A.S. Khimunin, illustrates the working principle of the technique used inrealizing level and distance measurements with an example on collisionavoidance and monitoring of empty parking lots 7.
3.4 SelectionBefore selecting anultrasonic sensor to use, it is necessary and important to check how theacoustical fundamentals will affect the echo being produced; as there are manydifferent ultrasonic sensor available with different frequencies and withdifferent radiation angles 8. The right selection of ultrasonic sensorparameters, will lead to better optimization of the system performance. 4 ConclusionI found that real-time embedded system technology has become amajor target for safty in automotive systems.
The use of the right andefficient sensors and powerful processors will enable these diminutive systems providegreat benefits to vehicle operators. The ongoing systems in development, areheading towards highway networks of driverless smart vehicles and automatedparking (AVs). Ultrasonic sensor systems are very good when parking in narrowplaces but can easily be affected by environmental factors. They are moreexpensive when compared with electromagnetic system sensors. Equipped with anunderstanding of sensors operations, automotive designers can easily select sensorsthat are efficient and powerful for advanced driver assistance systems whiledelivering optimum performance.